• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Need circuit help? Post them in the comments! I've answered over 50,000!

Blog | Categories | About | Contact | Calculators-online
You are here: Home / Battery Charger Circuits / Battery Cut Off Charger Circuit Using a Single Relay
simplestbatterychargercircuit

Battery Cut Off Charger Circuit Using a Single Relay

Last Updated on June 15, 2019 by Swagatam 31 Comments

Amazed to hear this! Yep that’s actually possible, you would need only one relay and a handful of diodes to make a simplest one relay automatic battery charger circuit.

Table of Contents
  • How it Works

How it Works

The idea struck me while trying to design the easiest possible battery charger circuit for one my clients.

The concept is simple; just raise the operating or triggering voltage of the relay up to the optimal battery charging threshold voltage by dropping the required amount of supply voltage to the relay coil, with the help of series diodes.The idea may be understood from the following points:

Take an ordinary relay, measure its triggering voltage by carefully applying a variable voltage across its coil.Now suppose the triggering voltage of the particular relay was about 9 volts, and also assume you want to raise its voltage to 14 volts, which may be your 12 volt battery’s charging threshold voltage.

We know that a 1N4007 diode drops about 0.6 volts across it, so if we add sufficient number of diodes in series with the relay coil would hopefully pull its tripping or triggering voltage to about 14 volts.

That means, 14 – 9 = 5, we’ll require 5/0.5 = 10 diodes in series to achieve this rise in the triggering voltage of the relay.That’s pretty simple and interesting isn’t it?The rest may be done with the help of the shown diagram…..your simplest single relay automatic battery charger is ready.

warning message: electricity is dangerous, proceed with caution

You'll also like:

  • 1.  Arduino Battery Level Indicator Circuit
  • 2.  Single Transformer Inverter/Charger Circuit
  • 3.  Lipo Battery Balance Charger for Charging of Series Connected Lipo Cells
  • 4.  Battery Charger Problems Troubleshooting Discussed
  • 5.  Battery Deep Discharge Protection Circuit
  • 6.  How to Calculate Solar Panel, Inverter, Battery Parameters

Filed Under: Battery Charger Circuits Tagged With: Battery, Charger, Relay, Single

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

Previous Post: « Introduction to Schmitt Trigger
Next Post: SMD LED based Emergency Lamp Circuit »
Subscribe
Notify of
guest
guest
31 Comments
Inline Feedbacks
View all comments

Primary Sidebar

circuit simulator image

Subscribe to get New Circuits in your Email

Categories

  • Arduino Projects (90)
  • Audio and Amplifier Projects (132)
  • Automation Projects (17)
  • Automobile Electronics (101)
  • Battery Charger Circuits (83)
  • Datasheets and Components (105)
  • Electronics Theory (140)
  • Free Energy (37)
  • Games and Sports Projects (11)
  • Grid and 3-Phase (19)
  • Health related Projects (25)
  • Home Electrical Circuits (12)
  • Indicator Circuits (15)
  • Inverter Circuits (89)
  • Lamps and Lights (142)
  • Meters and Testers (71)
  • Mini Projects (46)
  • Motor Controller (64)
  • Oscillator Circuits (28)
  • Pets and Pests (15)
  • Power Supply Circuits (89)
  • Remote Control Circuits (50)
  • Security and Alarm (64)
  • Sensors and Detectors (103)
  • SMPS and Converters (29)
  • Solar Controller Circuits (59)
  • Temperature Controllers (42)
  • Timer and Delay Relay (49)
  • Transmitter Circuits (29)
  • Voltage Control and Protection (38)
  • Water Controller (36)

Other Links

  • Privacy Policy
  • Cookie Policy
  • Disclaimer
  • Copyright
  • Videos
  • Sitemap

People also Search

555 Circuits | 741 Circuits | LM324 Circuits | LM338 Circuits | 4017 Circuits | Ultrasonic Projects | SMPS Projects | Christmas Projects | MOSFETs | Radio Circuits | Laser Circuits | PIR Projects |

Social Profiles

  • Twitter
  • YouTube
  • Instagram
  • Pinterest
  • My Facebook-Page
  • Quora
  • Stack Exchange
  • Linkedin
  • Recent Comments

    • Swagatam on How to Convert a Low Power Inverter to a High Power Inverter
    • Swagatam on Simple Buck Converter Circuits using Transistors
    • NGANG on How to Convert a Low Power Inverter to a High Power Inverter
    • Swagatam on Make this 7 Segment Digital Clock with Beep Alert Circuit
    • Swagatam on Make this 7 Segment Digital Clock with Beep Alert Circuit

    © 2025 · Swagatam Innovations